The objectives of the proposed research are the study of the mechanisms of triglyceride hydrolysis and the factors which modulate it in adipose tissue and in the heart. The specific aims include separation and purification of the lipases in the whole tissue and its component parts, particularly the cytosol and the plasma membrane. The hormones (catecholamines, pituitary polypeptides, glucagon) which stimulate lipolysis will be examined in these systems as well as the drugs which block their effects. The methods include enzyme isolation procedures after cell isolation and subsequent study of the enzyme activities therein. In addition to the cell fractionation studies outlined, a major emphasis will be placed on triglyceride metabolism and the drugs and hormones which affect this process in isolated fat cells and the perfused heart. Since triglyceride metabolism is a major process which is altered in diabetes mellitus, studies of hormone and drugs actions on triglyceride metabolism will be carried out in normal animals and in several model systems of diabetes mellitus. BIBLIOGRAPHIC REFERENCE: Jesmok, G.J., Mogelnicki, S.R., Lech, J.J. and Calvert, D.N.: Effect of polyamines, ions and epinephrine on triolein hydrolyzing activity of rat ventricular extracts. J. Mol. Cell. Cardiology 8: (In Press) 1976.